This invention relates generally to door latch mechanisms, and more particularly, concerns a door latch mechanisms for a tractor cabs having internal and external handles.
In recent times increased emphasis has been placed on the comfort of the operator of a tractor. Two aspects of this emphasis have been to make the access and egress from the cab of the tractor as comfortable as possible, and making the cab esthetically pleasing to the operator.
The original cabs for tractors had doors which provided access and egress while protecting the operator from the elements, but the doors were rustic in character in that they had only an external sheet and an elemental door latch arrangement with nominal consideration given to the esthetics of the door and the comfort of the operator. To improve both these aspects of the cab door, an internal door sheet was added to remove the door structure from the operator's sight and a dual handle arrangement was developed to increase the ease in access and egress from the cab.
In examining the dual door handle arrangement, it was determined that the most convenient handles were those which would provide cooperating unlatching and door opening motions. In a tractor cab the external door handle will optimumly be one which is located near the hinge connection of the door and one which utilizes a pivotal unlatching motion, thereby providing the operator with a pull lever for opening the door after unlatching the door catch. Similarly, it was determined that the optimum internal handle for a tractor cab is one positioned further from the door hinges than the external handle and one having a similar pivotal unlatching action thereby providing a push point for opening the door from within the cab.
Since a tractor must be dependable in spite of its operation in a rugged terrain, the linkage arrangement for the dual handle cab door must be durable. The arrangement must also be reasonably serviceable to avoid accessive down times during harvesting and planting operations.
Accordingly, it is the primary aim of the present invention to provide a door's latch mechanism for a tractor cab which optimizes the ease of access and egress and the esthetics of the cab while maintaining the durability of the unit.
Moreover, it is an object of the present invention to provide such a door like mechanism that is also easily serviceable to minimize maintenance and repair time.